The motion of a particle of a mass m is describe by $ y = ut + {1 \over 2 } gt^2 $ Find the force acting on the particle.
The given equation of motion is $ y = ut + \frac{1}{2}gt^2 $. This equation represents the vertical motion of a particle under the influence of gravity. The force acting on the particle is due to gravity, which is given by $ F = mg $. Hence, the correct option is F = mg.

